In order to decrease fuel consumption and exhaust emissions of internal combustion engines, and reduce size and weight of engines, it is highly desirable to eliminate the use of cylinder liners which are used to line aluminum cylinder blocks. As an alternative, thermal spraying to form sprayed coatings on inner surfaces of cylinder bores is being considered.
In the case of applying thermal spraying to a cylinder bore, a thermal spraying gun for providing a spraying material to a cylinder bore is rotated in the cylinder bore while moving in an axial direction to form a sprayed coating. Then, the surface of the coating on the cylinder bore is subjected to finish polishing such as honing.
In association with such a process, Patent Document 1 describes a process of removing an edge portion of an inner surface of a cylinder bore on a crankcase side, in order to prevent detachment of a sprayed coating especially on the crankcase side. In other words, the inner surface of the cylinder bore is removed including the edge portion of the sprayed coating on the crankcase side after the formation of the sprayed coating in such a manner that the internal diameter of the cylinder bore at the edge portion of the sprayed coating on the crankcase side is increased.